The present invention relates to sheet forming apparatuses and roller gap control methods, and more particularly to a sheet forming apparatus and a roller gap control method using a touch roller to form a sheet by passing through the sheet between two rollers so that both surfaces of the sheet contact the two rollers.
Sheet forming apparatuses using a extrusion molding method, disclosed in Japanese Patent Laid-Open Publications No.H9-155948 and No.H10-34748, comprise two rollers placed in parallel at a distance. The sheet forming apparatuses form a sheet by passing through the sheet (melted resin supplied from T-die) between the rollers which are rotatively driven, so that the both surfaces of the sheet contact the rollers.
The rollers have roller supporting housings (bearing housing), respectively, between which a wedge member is inserted with a gap. Since one roller supporting housing is pressed against the other roller supporting housing by means of a hydraulic cylinder apparatus, the gap is adjusted by controlling the insertion depth of the wedge member.